We are interested in examining the cerebrospinal fluid of patients suffering from neuropsychiatric disorders for altered levels of neurotransmitter. In preliminary studies, we have noticed decreased levels of gamma-aminobutyric acid (GABA) in patients diagnosed as having Huntington's Disease. We have recently demonstrated that 3-quinuclidinyl benzilate (QNB), GABA and spiroperidol radiolabeled to a high specifc activity bind to acetylcholine (muscarinic), GABAergic and dopaminergic receptors, respectively in the mammalian brain. Using these receptor binding assays, we have in preliminary studies found decreases in 3 H-QNB binding in several areas of b brains of patients who died of Huntington's Disease.